COMPMID-930 Disable warning about implicit-fallthrough in new versions of GCC

Change-Id: Ibbacb65cb84ccfb64960ac00c482040353be468c
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/120875
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>
diff --git a/SConstruct b/SConstruct
index 7f06a37..82100de 100644
--- a/SConstruct
+++ b/SConstruct
@@ -84,7 +84,7 @@
          '-Wextra','-Wno-unused-parameter','-pedantic','-Wdisabled-optimization','-Wformat=2',
          '-Winit-self','-Wstrict-overflow=2','-Wswitch-default',
          '-fpermissive','-std=gnu++11','-Wno-vla','-Woverloaded-virtual',
-         '-Wctor-dtor-privacy','-Wsign-promo','-Weffc++','-Wno-format-nonliteral','-Wno-overlength-strings','-Wno-strict-overflow'])
+         '-Wctor-dtor-privacy','-Wsign-promo','-Weffc++','-Wno-format-nonliteral','-Wno-overlength-strings','-Wno-strict-overflow','-Wno-implicit-fallthrough'])
 
 env.Append(CPPDEFINES = ['_GLIBCXX_USE_NANOSLEEP'])